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That's the claim by Devra Davis, whose book "Disconnect" says that cellular radiation weakens everything from sperm to hearing to memory to cancer resistance. Davis visited San Francisco to give a talk to the posh Commonwealth Club, where she called for decreasing usage. Or simply turning the phone off.

Are the trade show attendees concerned about health? Not especially, judging by the schedule of events. Although events are scheduled on topics like "Smart Energy Management" and applications for doctors, there's scant acknowledgment of the alleged health risks of cellphones.

Maybe that's because the issue is still far from settled. Cell phones might affect our health -- they do emit radiation, after all -- but nobody can agree on the extent of those effects. The only way to know for sure is to conduct long-term studies and see what happens. In 30 years, we'll know for sure.